1. Field of the Invention
The present invention generally relates to a video signal transmission technique, and is more specifically directed to such a video signal transmission technique for multiplexing digital R, G, B signals corresponding to video output signals to output the multiplexed digital R, G, B video signals.
2. Description of the Related Art
Conventionally, as video signal transmitting apparatuses, for example, Japanese Unexamined Patent Application No. 04-013392 opened in 1992 discloses the video transmitting apparatus (related art 1), and Japanese Unexamined Patent Application No. 04-355589 opened in 1992 describes the color video signal transmission method and the color video signals transmitting/receiving apparatus (related art 2). In the video transmitting apparatus of related art 1, the broad-band analog R, G, B signals are multiplexed in the 3-phase time divisional manner, and then the multiplexed broad-band analog R, G, B signals are transmitted via a single optical fiber. In the color video signals transmitting/receiving apparatus of related art 1, the digital video signal which has been multiplex-modulated in the time divisional manner by the video signal transmitting apparatus is transmitted via a single transmission cable to the video signal receiving apparatus.
As previously explained, when the respective signal components of the R, G, B video signals are multiplexed in the time divisional manner and the multiplexed R, G, B video signals are transmitted, these video signals can be transmitted by employing a single transmitting means. For instance, in the case that each of digital R, G, B video signals is D/A-converted into each of analog R, G, B video signals to be outputted, since these analog R, G, B video signals are multiplexed in the time divisional manner, a total number of D/A converters and a total path number of signal transmission paths can be reduced from 3 to 1.
In these conventional video signal transmitting and/or receiving apparatuses, since the time-division multiplexing technique is employed, the total quantities of the D/A converter and the signal transmission path can be reduced to 1, respectively. However, the timing signal used to notify the timing of the multiplexing operation must be transmitted independently from the transmissions of the three multiplexed R, G, B video signals. Therefore, such a transmitting apparatus for transmitting this timing signal is necessarily required. In other words, on the reception side where the video signals which have been D/A-converted to be transmitted are received, these multiplexed analog video signals are demultiplexed to produce a plurality of original video signals based upon the timing signal indicative of the timing of the multiplexing operation after A/D-converting the video signals.